In an LTE (long term evolution) system, there are multiple defined system bandwidths, such as 1.4 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz. A system bandwidth may be further divided into some sub-bands. That is, a sub-band is a length of consecutive frequency domain resources (a bandwidth of the sub-band is generally less than or equal to 1.4 MHz) that is in the system bandwidth and that is less than the system bandwidth. Generally, a PRB (physical resource block) is used as a unit.
Currently, a base station generally configures one or more sub-bands for UE in a broadcasting manner, so that the UE communicates with the base station in a corresponding frequency band by using the sub-bands configured by the base station. That is, the UE may use only one or more fixed frequency bands to communicate with the base station. In this way, when the sub-bands configured by the base station for the UE have relatively poor communication performance, and the UE can use only the configured sub-bands to communicate with the base station, the UE may not normally interact with the base station in an excessively long time. This reduces quality of communication between the UE and the base station and resource utilization of each sub-band in the system bandwidth.